import java.io.*;
import java.util.zip.CheckedInputStream;
import java.util.zip.CheckedOutputStream;
import java.util.zip.CRC32;
import org.apache.commons.net.ftp.*;

public class Main implements java.io.Serializable
{
    public static void main(String[] args) throws Exception
    {
        Main main = new Main();
        main.doTest();
    }

    private void doTest() throws Exception
    {
        String host = "ftp.host.com";
        String user = "user";
        String pass = "pass";

        String asciiDest = "/tmp/ascii";
        String binaryDest = "/tmp/binary";

        String remotePath = "test/";
        String remoteFilename = "test.xml";

        System.out.println("TEST.XML ASCII");
        MyFTPClient client = createFTPClient(host, user, pass, org.apache.commons.net.ftp.FTP.ASCII_FILE_TYPE);
        File path = new File("/tmp/ascii");
        downloadFTPFileToPath(client, "test/", "test.xml", path);
        System.out.println("");

        System.out.println("TEST.XML BINARY");
        client = createFTPClient(host, user, pass, org.apache.commons.net.ftp.FTP.BINARY_FILE_TYPE);
        path = new File("/tmp/binary");
        downloadFTPFileToPath(client, "test/", "test.xml", path);
        System.out.println("");

        System.out.println("TEST.MP3 ASCII");
        client = createFTPClient(host, user, pass, org.apache.commons.net.ftp.FTP.ASCII_FILE_TYPE);
        path = new File("/tmp/ascii");
        downloadFTPFileToPath(client, "test/", "test.mp3", path);
        System.out.println("");

        System.out.println("TEST.MP3 BINARY");
        client = createFTPClient(host, user, pass, org.apache.commons.net.ftp.FTP.BINARY_FILE_TYPE);
        path = new File("/tmp/binary");
        downloadFTPFileToPath(client, "test/", "test.mp3", path);
    }

    public static File downloadFTPFileToPath(MyFTPClient ftp, String remoteFileLocation, String remoteFileName, File path)
        throws Exception
    {
        // path to remote resource
        String remoteFilePath = remoteFileLocation + "/" + remoteFileName;

        // create local result file object
        File resultFile = new File(path, remoteFileName);

        // local file output stream
        CheckedOutputStream fout = new CheckedOutputStream(new FileOutputStream(resultFile), new CRC32());

        // try to read data from remote server
        if (ftp.retrieveFile(remoteFilePath, fout)) {
            System.out.println("FileOut: " + fout.getChecksum().getValue());
            return resultFile;
        } else {
            throw new Exception("Failed to download file completely: " + remoteFilePath);
        }
    }

    public static MyFTPClient createFTPClient(String url, String user, String pass, int type)
        throws Exception
    {
        MyFTPClient ftp = new MyFTPClient();
        ftp.connect(url);
        if (!ftp.setFileType( type )) {
            throw new Exception("Failed to set ftpClient object to BINARY_FILE_TYPE");
        }

        // check for successful connection
        int reply = ftp.getReplyCode();
        if (!FTPReply.isPositiveCompletion(reply)) {
            ftp.disconnect();
            throw new Exception("Failed to connect properly to FTP");
        }

        // attempt login
        if (!ftp.login(user, pass)) {
            String msg = "Failed to login to FTP";
            ftp.disconnect();
            throw new Exception(msg);
        }

        // success! return connected MyFTPClient.
        return ftp;
    }
}